Thursday, July 29, 2010

We all remember a moment in which a teacher or mentor made a difference in our lives. It could be a nod of encouragement, a helping hand, a lesson that inspired wonder or discovery, and ultimately may have given purpose and value to our lives.

These moments of awareness are what educators and mentors at NASA Ames Research Center, Moffett Field, Calif. hoped to inspire in our new generation on July 26, 2010, when it celebrated scientific discovery and technological innovation as part of its Summer of Innovation initiative. “Exploration Day” featured out-of-this-world missions and technology programs that brought students to NASA, so that they might experience a sense of awe and excitement while learning about NASA and its missions at the same time.

“Our research community has done a tremendous job developing new and creative ways to engage young people in their fields,” said S. Pete Worden, director at NASA Ames. “They have been doing their part to speak at schools, to create hands-on learning opportunities as mentors, and to help spark that same curiosity in students which perhaps led them to pursue a career in science and engineering.”

NASA Ames organized a day filled with science, technology, engineering and mathematics (STEM) education hands-on activities and events, including a visit from the Traveling Space Museum (TSM), the “grand opening” of the renovated Ames Exploration Encounter (AEE), an opportunity to operate the rovers on a simulated lunar regolith and a student poster session of more than 100 students.

TSM brought to Ames numerous hands-on activities, one of which was “moon boots.” Who wouldn’t want to simulate Neil Armstrong’s zero-gravity walk on the moon? By strapping on a pair of “moon boots,” young students walked with enough bounce to simulate a feeling of zero-gravity, or a less firm terrain. The boots also were large enough to leave behind a giant footprint.

Another activity included an authentic BD-5J micro jet with operating controls similar to a hang glider. Young, novice pilots waited patiently to fly the small, single-seated aircraft, which demonstrated rudder movement when they pumped the foot pedals.

At a space shuttle exhibit, students learned to give the module operator a “thumbs up” to start the engine, and they were invited to “have a seat” on the space shuttle waste containment system (space toilet) to experience what it’s like to live and work in space. The sudden suction of air caused one boy to exclaim, “Wow! It’s breezy.”

The Ames Exploration Encounter always is a popular student science facility that provides hands-on activities exploring physics, flight, space science and Earth science. It was completely renovated just in time for the Summer of Innovation celebration.

AEE’s renovation included even more STEM education hands-on activities for middle school students. To help children learn math, AEE invested in 12 computer stations to challenge students’ math skills while landing a large aircraft in a variety of conditions. The NASA-developed, computer learning program is called “Smart Skies,” which enables students to explore and resolve distance-rate-time problems in realistic air traffic control problems using decision-making and proportional reasoning skills.

Other new AEE interactive modules include a 2012 NASA mission, called the Lunar Atmosphere and Dust Environment Explorer (LADEE), a lunar lander, and an International Space Station mock-up, remote operations of a rover on simulated regolith and other activities as well.

“I couldn’t have imagined a better opening for our new AEE facility. During the day, we had more than 800 excited and enthusiastic guests,” said Brenden Sanborn, education specialist and AEE manager. “I am hard-pressed to tell who enjoyed it more, the children or the adults.”

The celebration also included a student poster session, which illustrated and explained the accomplishments of the undergraduate interns and graduate fellows who worked at Ames. Students also used their posters as part of a presentation to fellow students and NASA mentors.

“The Ames Education Office was proud to show all the hard work performed by our undergraduate interns and graduate fellows. During their time here, they contributed to NASA missions and status,” said Brenda Collins, Higher Education program manager at NASA Ames. ”We can look forward to welcoming these bright young minds into the future workforce.”

Ames’ Exploration Day was about providing positive experiences in science and mathematics, and instilling in young people a love of learning and a sense of possibility in their own lives. As children moved from one event to the other, many of them were heard to say: “Thanks for the ride. It was fun!”

Wednesday, July 28, 2010

Recently, technicians at NASA's Marshall Space Flight Center in Huntsville, Ala., completed a series of cryogenic tests on six James Webb Space Telescope beryllium mirror segments at the center's X-ray & Cryogenic Facility. During testing, the mirrors were subjected to extreme temperatures dipping to -415 degrees Fahrenheit, permitting engineers to measure in extreme detail how the shape of the mirror changes as it cools.

The Webb telescope has 18 mirrors, each of which will be tested twice in the Center's X-ray & Cryogenic Facility to ensure that the mirror will maintain its shape in a space environment -- once with bare polished beryllium and then again after a thin coating of gold is applied.

The cryogenic test gauges how each mirror changes temperature and shape over a range of operational temperatures in space. This helps predict how well the telescope will image infrared sources.

The mirrors are designed to stay cold to allow scientists to observe the infrared light they reflect using a telescope and instruments optimized to detect this light. Warm objects give off infrared light, or heat. If the Webb telescope mirror is too warm, the faint infrared light from distant galaxies may be lost in the infrared glow of the mirror itself. Thus, the Webb telescope's mirrors need to operate in a deep cold or cryogenic state, at around -379 degree Fahrenheit.

Tuesday, July 27, 2010

Flight Engineers Fyodor Yurchikhin and Mikhail Kornienko concluded a six-hour, 42-minute spacewalk Tuesday at 6:53 a.m. EDT. The cosmonauts began their spacewalk when they opened the hatches of the Pirs docking compartment at 12:11 a.m. This was the 147th spacewalk overall in support of International Space Station assembly and maintenance.

The cosmonauts wore their Russian Orlan spacesuits to outfit the new Rassvet module for a Kurs automated rendezvous system capability for future dockings of Russian vehicles arriving at the station to link up to Rassvet. They also routed and mated Command and Data Handling cables on the Zvezda and Zarya modules.

A video camera was removed and replaced on the aft end of Zvezda then successfully tested. The old camera was safely jettisoned away from the station. The new camera will be used to provide television views of the final approach and docking of future European Automated Transfer Vehicles carrying cargo to the complex.

During the spacewalk, two objects were detected floating away from the station. One was tentatively identified as a cable clamp, left outside the station from a previous Russian spacewalk. That object and another, not conclusively identified, both departed well below the vicinity of the complex and pose no threat to the orbiting laboratory.

This was Kornienko’s first spacewalk and Yurchikhin’s fourth. Yurchikhin’s first three spacewalks occurred when he was commander of Expedition 15 in 2007.

The second spacewalk of Expedition 24 is planned for August 5 by Flight Engineers Doug Wheelock and Tracy Caldwell Dyson in U.S. spacesuits out of the Quest airlock. They will install a power cable to the Unity module in preparation for the installation of the Permanent Multipurpose Module during the STS-133 mission in November. A Portable Data Grapple Fixture will be installed on the Zarya module that will extend the reach of Canadarm2, the station’s robotic arm, and increase a spacewalker’s access for assembly or maintenance work. They also will jettison multi-layer insulation removed for the grapple fixture installation and will mate power connectors to Zarya.

Caldwell Dyson will be making the first spacewalk of her career. Wheelock will be conducting his fourth. His first three spacewalks occurred as a mission specialist during STS-120 in late 2007.

Adjusting their schedule to support Monday night’s spacewalk, the International Space Station operations team met late yesterday to review results of last week’s dry run for using Canadarm2 and its Dextre robotic helper to replace a failed Remote Power Control Module (RPCM) in the P1 truss. The team elected to defer additional work with Dextre until additional analysis of the forces required to remove the smart circuit breaker from its housing in the truss is completed.

The delay will not affect plans for the upcoming spacewalk by Wheelock and Caldwell Dyson. Power systems on the station are operating well with the failed RPCM in its current installed position.

Monday, July 26, 2010

The Orion Nebula is a 'happening' place where stars are born and this colony of hot, young stars is stirring up the cosmic scene in this image from NASA's Spitzer Space Telescope. The young stars dip and peak in brightness; shifting cold and hot spots on the stars' surfaces cause brightness levels to change. In addition, surrounding disks of lumpy planet-forming material can obstruct starlight. Spitzer is keeping tabs on the young stars, providing data on their changing ways. The hottest stars in the region are the Trapezium cluster.

This image was taken after Spitzer's liquid coolant ran dry in May 2009, marking the beginning of its "warm" mission.

Sunday, July 25, 2010

A half-dozen enthusiastic Southern California elementary and high school teachers learned to use NASA education resources this summer while indentifying and creating new educational opportunities for teachers and students through the agency's Airborne Research Experiences for Educators and Students program.

The six educators from Santa Clarita, Los Angeles, Lancaster and Palmdale were competitively selected to participate in an AREES summer workshop held June 21 through July 16 in Palmdale, Calif. The workshop was designed to help participants identify and implement educator and student activities in the areas of science, technology, engineering and math, or STEM, disciplines that leverage the wide variety of aircraft, flight missions and research opportunities across NASA.

The AREES initiative supports NASA’s commitment to STEM education by providing K-12 educators and students with NASA content-based resources, materials and instructional and enrichment activities. Through the program, teachers are developing curricula and activities for the upcoming school year,

On June 29 and again on July 8, the group participated in science missions flown by a Gulfstream-III research aircraft equipped with a sophisticated synthetic aperture radar system developed by NASA’s Jet Propulsion Laboratory. The flights from the Dryden Aircraft Operations Facility in Palmdale, Calif., collected radar data for earthquake and soil moisture studies, and provided the educators with insight on NASA 's collection methodology.

Participating in the mission "made me realize that I have been missing the boat entirely by not having such incredible, high-level, stimulating activities that align with the students’ curriculum standards," said Bobbie Mitchell, an eighth-grade algebra teacher at Lancaster’s Amargosa Creek Middle School. "I need to get students excited about learning and show them that they have a great future here in the Antelope Valley."

In her classes, Mitchell said she begins each school year by asking students, "Who likes math?" Often, she says, no one raises a hand.

But another of the six educators chosen for the workshop, Maria Blue, a first-grade teacher at Santa Clarita’s Plum Canyon Elementary School, said her students often say that they like math, leading Mitchell and Blue to wonder what happens to make students lose interest in math between elementary and middle school.

The other teachers who were involved in this summer’s AREES program were Marlene McShea, who teaches biology and chemistry at Lancaster’s Paraclete High School; Julie Bookman, a biology teacher at Palmdale High School; Douglas Phelps, who teaches chemistry at the SAGE Academy at Belmont High School in Sherman Oaks, Calif.; and Sonja Steffan-Squires, a science teacher at Joe Walker Middle School in Quartz Hill, Calif.

“AREES provides a way for educators to engage in cutting-edge airborne science research and technology,” said Vikki Costa, a faculty consultant from California State University Fullerton. “The program includes guidance in the translation of these experiences into multi-disciplinary K-12 curricula that provides students with the most current information about critical science issues including climate change, weather and earthquake monitoring. Through investigations, engineering design challenges, and project-based learning, students also explore future careers in STEM fields.”

The AREES program goal is to stimulate interest in NASA's Earth Science research and, with the help of educators, support recruitment of the agency’s future engineers and scientists, said AREES project manager Shaun Smith.

“We use unique NASA resources to inspire the next generation of explorers,” Smith added. “We’re doing that through the aircraft, the missions and the science behind the missions. We have access to platforms, technical personnel and access to actual flights.”

Smith said the ultimate goal of the summer program is to make the instructional materials developed by teachers in the AREES workshops available at the national level, as well as to extend the program to other areas across the nation.

The six teachers who participated in this year’s AREES workshop will receive professional development hours that can be applied toward maintaining their teaching credential. They also have the option to receive three graduate-level credits from California State University, Fullerton.

The AREES program is co-sponsored by NASA Dryden Flight Research Center’s Office of Education and the Teaching From Space program at NASA’s Johnson Space Center in Houston, in partnership with the Aerospace Education Research and Operations Institute in Palmdale, Calif., and California State University, Fullerton.

Friday, July 23, 2010

Mars Curiosity team members gather in the clean room at NASA's Jet Propulsion Laboratory to watch the rover roll for the first time - Larger ImageLike proud parents savoring their baby's very first steps, mission team members gathered in a gallery above a clean room at NASA's Jet Propulsion Laboratory to watch the Mars Curiosity rover roll for the first time.

Engineers and technicians wore "bunny suits" while guiding Curiosity through its first steps, or more precisely, its first roll on the clean room floor. The rover moved forward and backward about 1 meter (3.3 feet).

Mars Science Laboratory (aka Curiosity) is scheduled to launch in fall 2011 and land on the Red Planet in August 2012. Curiosity is the largest rover ever sent to Mars. It will carry 10 instruments that will help search an intriguing region of the Red Planet for two things:1. Environments where life might have existed2. The capacity of those environments to preserve evidence of past life

Thursday, July 22, 2010

NASA's Mars Odyssey orbiter put itself into a safe standby mode on Wednesday, July 14, and the team operating the spacecraft has begun implementing careful steps designed to resume Odyssey's science and relay operations this week.

Engineers have diagnosed the cause of the safe-mode entry as the spacecraft's proper response to unexpected performance by an electronic encoder. That encoder controls motion of a gimbal that adjusts the position of the solar array. Odyssey switched to a redundant encoder, and there is no sign of any mechanical problem with the gimbal.

Commands from Earth have switched Odyssey back to using its high-gain antenna. The programmed response to the detected problem on July 14 initially shifted the spacecraft to slower communication via its low-gain antenna.

The spacecraft team recovered downward-pointing operations, out of safe mode, on Friday, July 16. "We expect to be back to full operations this week," said Odyssey Project Manager Phil Varghese of NASA's Jet Propulsion Laboratory, Pasadena, Calif.

Odyssey has been orbiting Mars since 2001. In addition to its own major scientific discoveries and continuing studies of the planet, the Odyssey mission has played important roles in supporting the missions of the Mars rovers Spirit and Opportunity and the Phoenix Mars Lander.

The rover Opportunity was not able to transmit data to ground controllers via Odyssey while the orbiter was in safe mode. Science activities were delayed, but critical activities have not been affected.

JPL, a division of the California Institute of Technology in Pasadena, manages Mars Odyssey for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.

Tuesday, July 20, 2010

Preparations are under way for the testing of NASA's next-generation, five-segment solid rocket development motor -- DM-2 -- in September. The test is designed to advance the understanding, safety, technology and capability of solid rocket motors.

The five-segment DM-2 motor -- capable of producing 22 million horsepower and generating as much as 3.6 million pounds of thrust -- was developed by ATK Space Systems, a division of Alliant Techsystems of Brigham City, Utah, the prime contractor for the solid rocket motor, and is being assembled at ATK's test stand in Promontory, Utah. This will be the second, full-scale, full-duration test of the new development motor, which follows the successful test of DM-1 last fall.

"The successful DM-1 test provided our team with great results," said Andy Schorr, first stage, five-segment motor lead for Ares Projects at NASA's Marshall Space Flight Center in Huntsville, Ala. "All performance measurements were within specified limits and 46 total objectives, covering each significant design feature of the motor, were met.

During this "cold motor" test, DM-2's overall temperature will be lowered to 40 degrees Fahrenheit to validate the motor's performance in cold weather. This is in contrast to the DM-1 test firing which was conducted at ambient temperature. As the test is conducted, technicians will collect data from 759 sensors to assess the motor's performance and validate motor enhancements. Measurements gathered will be used to evaluate thrust, roll control, acoustics, motor vibrations, nozzle modifications and insulation upgrades.

Although similar to the solid rocket boosters that help power the space shuttle to orbit, DM-2 includes several upgrades and technology improvements, including the addition of a fifth segment, a modified nozzle throat and upgraded insulated liner. With these changes, engineers hope to improve performance and provide greater safety and reliability for NASA's next-generation launch vehicle.

"Our team is responsible for developing a robust propulsion system that can provide the thrust necessary to escape Earth's gravitational well and safely deliver astronaut crews and payloads to the International Space Station and beyond," Schorr said. "As we press forward, our goal is to optimize every aspect of the system for peak performance."

Large, solid rocket motors have been a primary propulsion element in modern space exploration – used as booster motors for the space shuttle, Atlas V and Delta IV rockets and several military applications. They provide high thrust, or lifting power, for relatively low cost, and do not have the more costly refrigeration and insulation requirements of cryogenic liquid-fueled rockets.

A development test motor is used to simulate conditions experienced in flight. It offers engineers an opportunity to better assess the strength of the motor's current design, spot any flaws in the new designs, verify new materials and certify manufacturing processes.

"Tests such as DM-2 allow our team to improve and enhance existing technology essential to maintaining America's preeminence in space, even as we look to new designs, new materials and new technologies with the potential to transform the future of human spaceflight," he said.

Sunday, July 18, 2010

NASA-funded researchers are monitoring a big event in our planet's atmosphere. High above Earth's surface where the atmosphere meets space, a rarefied layer of gas called "the thermosphere" newly collapsed and now is rebounding again.

"This is the biggest contraction of the thermosphere in at least 43 years," says John Emmert of the Naval Research Lab, lead author of a paper announcing the finding in the June 19th concern of the Geophysical Research Letters (GRL). "It's a Space Age record."

The collapse happened during the deep solar minimum of 2008-2009—a fact which comes as little revelation to researchers. The thermosphere always cools and contracts when solar activity is low. In this case, however, the magnitude of the collapse was two to three times greater than low solar activity could explain.

"Something is going on that we do not understand," says Emmert.

The thermosphere ranges in altitude from 90 km to 600+ km. It is a realm of meteors, auroras and satellites, which skim through the thermosphere as they circle Earth. It is also where solar radiation makes first contact with our planet. The thermosphere intercepts extreme ultraviolet (EUV) photons from the sun before they can arrive at the ground. When solar activity is high, solar EUV warms the thermosphere, causing it to puff up like a marshmallow held over a camp fire. (This heating can raise temperatures as high as 1400 K—hence the name thermosphere.) When solar activity is low, the opposite happens.

Lately, solar activity has been very low. In 2008 and 2009, the sun plunged into a century-class solar minimum. Sunspots were scarce, solar flares almost non-existent, and solar EUV radiation was at low ebb. Researchers immediately turned their attention to the thermosphere to see what would happen.

How do you know what's happening all the way up in the thermosphere?

Emmert uses a clever technique: Because satellites feel aerodynamic drag when they move through the thermosphere, it is probable to monitor conditions there by watching satellites decay. He analyzed the decay rates of more than 5000 satellites ranging in altitude between 200 and 600 km and ranging in time between 1967 and 2010. This provided a unique space-time sampling of thermospheric density, temperature, and pressure covering almost the entire Space Age. In this way he discovered that the thermospheric collapse of 2008-2009 was not only bigger than any previous collapse, but also bigger than the sun alone could explain.

One possible explanation is carbon dioxide (CO2).

When carbon dioxide gets into the thermosphere, it acts as a coolant, shedding heat via infrared radiation. It is widely-known that CO2 levels have been increasing in Earth's atmosphere. Extra CO2 in the thermosphere could have magnified the cooling action of solar minimum.

"But the numbers don't quite add up," says Emmert. "Even when we take CO2 into account using our best understanding of how it operates as a coolant, we cannot fully explain the thermosphere's collapse."

According to Emmert and colleagues, low solar EUV accounts for about 30% of the collapse. Extra CO2 accounts for at least another 10%. That leaves as much as 60% unaccounted for.

In their GRL paper, the authors acknowledge that the situation is complicated. There's more to it than just solar EUV and terrestrial CO2. For instance, trends in global climate could alter the composition of the thermosphere, changing its thermal properties and the way it responds to external stimuli. The overall sensitivity of the thermosphere to solar radiation could actually be increasing.

"The density anomalies," they wrote, "may signify that an as-yet-unidentified climatological tipping point involving energy balance and chemistry feedbacks has been reached."

Or not.

Important clues may be found in the way the thermosphere rebounds. Solar minimum is now coming to an end, EUV radiation is on the rise, and the thermosphere is puffing up again. Exactly how the recovery proceeds could unravel the contributions of solar vs. terrestrial sources.

Thursday, July 15, 2010

The first spacecraft intended by NASA to orbit Mercury is giving scientists a new perspective on the planet's atmosphere and evolution.

Launched in August 2004, the Mercury Surface, Space Environment, Geochemistry and Ranging spacecraft, recognized as MESSENGER, conducted a third and final flyby of Mercury in September 2009. The probe finished a critical maneuver using the planet's gravity to remain on course to enter into orbit around Mercury next year.

Data from the final flyby has revealed the first observations of ion emissions in Mercury's exosphere, or thin atmosphere; new in order about the planet's magnetic substorms; and evidence of younger volcanic activity than previously recorded. The results are reported in three papers published online in the July 15 edition of Science Express.

The distribution of individual chemical elements that the spacecraft saw in Mercury’s exosphere varied around the planet. Detailed elevation profiles of those elements in the exosphere over the north and south poles of the planet were also measured for the first time.

"These profiles showed substantial variability among the sodium, calcium, and magnesium distributions, indicating that numerous processes are at work and that a given process may affect each element quite differently," said Ron Vervack, lead author of one of the papers and the spacecraft's participating scientist at the Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Md.

Emission from ionized calcium in Mercury's exosphere was observed for the first time during the flyby. The emission was concentrated over a moderately small portion of the exosphere, with most of the emission occurring close to the equatorial plane.

During its first two flybys of Mercury, the spacecraft captured descriptions confirming that the planet's early history was marked by pervasive volcanism. The spacecraft's third flyby revealed a new chapter in that history within an impact basin 180 miles in diameter that is among the youngest basins yet seen. The basin, recently named Rachmaninoff, has an inner floor filled with smooth plains that differ in color from their surroundings. These sparingly cratered plains are younger than the basin they fill and apparently formed from material that once flowed across the surface.

"We interpret these plains to be the youngest volcanic deposits we have yet found on Mercury," said Louise Prockter, one of the spacecraft's assistant project scientists at APL and lead author of one of the three papers. "Other observations suggest the planet spanned a much greater duration volcanism than previously thought, perhaps extending well into the second half of solar system history."

For the first time, the spacecraft revealed substorm-like build-up, or loading, of magnetic energy in Mercury's magnetic tail. The increases in energy calculated in Mercury's magnetic tail were very large. They occurred quickly, lasting only two to three minutes from beginning to end. These increases in tail magnetic energy at Mercury are about 10 times greater than at Earth, and the substorm-like events run their course about 50 times more rapidly.

Magnetic substorms are space-weather disturbances that occur sporadically on Earth, usually several times per day, and last from one to three hours. Earth substorms are accompanied by a range of phenomena, such as the majestic auroral displays seen in the Arctic and Antarctic skies. Substorms also are associated with dangerous energetic particle events that can wreak havoc with communications and Earth-observing satellites.

"The tremendous tail loading and unloading observed at Mercury implies that the relative intensity of substorms must be much larger than at Earth," said James A. Slavin, a space physicist at NASA's Goddard Space Flight Center in Greenbelt, Md., and a member of the spacecraft's science team and lead author of another paper.

The new measurements give fresh insight on the time duration of Mercury's substorms. Scientists await more extensive measurements when the spacecraft is in orbit.

"Every time we've encountered Mercury, we've discovered new phenomena," said Sean Solomon, the mission's principal investigator at the Carnegie Institution of Washington. "We're learning that Mercury is an tremendously dynamic planet, and it has been so throughout its history. After MESSENGER has been safely inserted into orbit around Mercury next March, we'll be in for a terrific show."

In addition to flying by Mercury, the spacecraft flew past Earth in August 2005 and Venus in October 2006 and June 2007. Approximately 98 percent of Mercury's surface has been imaged by NASA spacecraft. After this spacecraft goes into orbit around Mercury for a yearlong study of the planet, it will observe the polar regions, which are the only unobserved areas of the planet.

The spacecraft was designed and built by APL. The mission is managed and operated by APL for NASA's Science Mission Directorate in Washington.

As the sun sets on July 8, 2010, workers prepare to pour new epoxy grout for the hydrostatic bearing assembly of the giant "Mars antenna" at NASA's Deep Space Network communications site in Goldstone, Calif. - Larger Image

Workers at NASA's Deep Space Network complex in Goldstone, Calif., have been making precise, laser-assisted measurements to make sure a flat surface for pouring new grout as part of a main renovation on the 70-meter-wide (230-foot-wide) "Mars antenna." While formally dubbed Deep Space Station 14, the antenna picked up the Mars name from its first task: tracking NASA's Mariner 4 spacecraft, which had been lost by smaller antennas after its historic flyby of Mars.

This work represents the first time network engineers have redesigned and replaced the hydrostatic bearing assemblage, which enables the antenna to rotate horizontally. To achieve this, they lifted the entire rotating structure of the giant antenna for the first time.

The hydrostatic bearing assembly puts the weight of the antenna on three pads, which glide on a film of oil around a large steel ring. The ring measures about 24 meters (79 feet) in diameter and must be flat to work professionally. After 44 years of near-constant use, the Mars antenna needed a kind of joint replacement, since the bearing assembly had become uneven.

Engineers and managers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., which manages the Deep Space Network for NASA, drew up plans for new runner segments, new sole plates below the runner segments, and an epoxy grout that is more resistant to oil. The thicker segments deform less when the antenna's pads pass over them, and allow for more tightly sealed joints.

Since beginning work in March, engineers and technicians have carefully lifted several million pounds of delicate scientific instruments about five millimeters (0.2 inches) and transferred the weight of the antenna to provisional supporting legs. They have removed the old steel runner and cement-based grout. They have also installed sole plates, which cover the grout and anchor the new runner. Over the past week, JPL engineers checked to make sure the sole plates were level, and workers poured the new epoxy grout underneath to hold them in place. Mixing and pouring the new grout occurred at night to ensure the work was completed within the tight temperature tolerances required to handle this material.

Over the next few weeks, the new, thicker steel runner segments will be installed. Work is on track to return the antenna to service on Nov. 1, 2010.

Tuesday, July 13, 2010

Engineers just installed six new wheels on the Curiosity rover, and rotated all six wheels at once on July 9, 2010. Credit: NASA/JPL-Caltech - Full image and caption

The wheels that will touch down on Mars in 2012 are numerous rotations closer to spinning on the rocky trails of Mars.

This video clip shows engineers in the JPL clean room where the rover is being assembled as they put all six wheels into action for the first time.

Engineers raised the rover just as a car mechanic would hoist a car to check the wheels, and started the "engine" to get the wheels rotating. The wheel mobility system has 10 motors in all-four for routing the rover and six for driving. During this test, all 10 motors ran in every direction. Each wheel spun forward and backwards.

Next up for Curiosity is a sequence of "tune-ups" to prep the rover for driving.

Monday, July 12, 2010

Once the radiation vault was installed on top of the propulsion module, NASA's Juno spacecraft was lifted onto a large rotation fixture to continue with its assembly process. Image Credit: NASA/JPL-Caltech/LMSS - Larger Image

NASA's Juno spacecraft will be forging ahead into a deceitful environment at Jupiter with more radiation than any other place NASA has ever sent a spacecraft, excluding the sun. In a particularly filtered cleanroom in Denver, where Juno is being assembled, engineers recently added an exclusive protective shield around its sensitive electronics. New pictures of the gathering were released today.

"Juno is essentially an armored tank going to Jupiter," said Scott Bolton, Juno's principal investigator, based at Southwest Research Institute in San Antonio. "Without its protective shield, or radiation vault, Juno's brain would get fried on the very first pass near Jupiter."

An invisible force field filled with high-energy particles coming off from Jupiter and its moons surrounds the leading planet in our solar system. This magnetic force field, similar to a less powerful one around Earth, shields Jupiter from charged particles flying off the sun. The electrons, protons and ions around Jupiter are thrilled by the planet's super-fast rotation, sped up to nearly the speed of light.

Jupiter's radiation belts are shaped like a huge doughnut around the planet's equatorial region and extend out past the moon Europa, about 650,000 kilometers (400,000 miles) out from the top of Jupiter's clouds.

"For the 15 months Juno orbits Jupiter, the spacecraft will have to withstand the equivalent of more than 100 million dental X-rays," said Bill McAlpine, Juno's radiation control manager, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "In the same way human beings need to protect their organs during an X-ray exam, we have to protect Juno's brain and heart."

The strategy? Give Juno a kind of six-sided lead apron on steroids.

With guidance from JPL and the principal investigator, engineers at Lockheed Martin Space Systems designed and built a special emission vault made of titanium for a centralized electronics hub. While other materials exist that make good radiation blockers, engineers chose titanium because lead is too soft to withstand the sensations of launch, and some other materials were too difficult to work with.

Each titanium wall measures nearly a square meter (nearly 9 square feet) in area, about 1 centimeter (a third of an inch) in thickness, and 18 kilograms (40 pounds) in mass. This titanium box -- about the size of an SUV's trunk - encloses Juno's command and data handling box (the spacecraft's brain), power and data distribution unit (its heart) and about 20 other electronic assemblies. The whole vault weighs about 200 kilograms (500 pounds).

The vault is not designed to completely prevent every Jovian electron, ion or proton from hitting the system, but it will dramatically slow down the aging effect radiation has on electronics for the duration of the mission.

"The centralized radiation vault is the first of its kind," Bolton said. "We basically designed it from the ground up."

When NASA's Galileo spacecraft visited Jupiter from 1995 to 2003, its electronics were shielded by special components designed to be resistant to radiation. Galileo also didn't need to survive the harshest radiation regions, where Juno will operate.

But Juno isn't relying solely on the radiation vault. Scientists designed a path that takes Juno around Jupiter's poles, spending as little time as probable in the sizzling radiation belts around Jupiter's equator. Engineers also used designs for electronics already approved for the Martian radiation environment, which is harsher than Earth's, though not as harsh as Jupiter's. Parts of the electronics were made from tantalum, or tungsten, another radiation-resistant metal. Some assemblies also have their own mini-vaults for protection.

Packing the assemblies next to each other allows them to shield their neighbors. In addition, engineers wrapped copper and stainless steel braids like chain mail around wires involving the electronics to other parts of the spacecraft.

JPL tested pieces of the vault in a radiation environment similar to Jupiter's to make sure the design will be able to handle the stress of space flight and the Jupiter environment, McAlpine said. In a special lead-lined testing tub there, they battered pieces of the spacecraft with gamma rays from radioactive cobalt pellets and analyzed the results for Juno's expedition.

The vault was lifted onto Juno's propulsion module on May 19 at Lockheed Martin's high-bay cleanroom. It will undergo further testing once the whole spacecraft is put together. The assembly and testing process, which also includes installing solar panels for the first-ever solar-powered mission to Jupiter, is expected to last through next spring. Juno is expected to launch in August 2011.

"The Juno assembly is proceeding well," said Tim Gasparrini, Lockheed Martin program manager. "We have a number of the flight and test unit spacecraft avionics components installed into the radiation vault for system testing and we have also just installed the first instrument, the microwave radiometer."

JPL manages the Juno mission for the principal investigator, Scott Bolton, of Southwest Research Institute at San Antonio, Texas. Lockheed Martin Space Systems, Denver, Colo., is building the spacecraft. The Italian Space Agency in Rome is contributing an infrared spectrometer instrument and a portion of the radio science experiment.

Sunday, July 11, 2010

As the arcing loops above an active region began to spin into a nice profile view, SDO captured the dynamic, magnetic struggles taking place below (July 6-8, 2010). Particles strengthening along magnetic field lines trace their paths. Magnetic forces in the active region are linking, breaking apart, and reconnecting. These images were taken in extreme ultraviolet light. Although mostly concealed from our view, the vigorous region did unleash a number of small flares.

Thursday, July 8, 2010

A propeller-shaped structure created by an unseen moon is brightly illuminated on the sunlit side of Saturn's rings in this image obtained by NASA’s Cassini spacecraft. Image Credit: NASA/JPL/SSI

Scientists using NASA's Cassini spacecraft at Saturn have stalked a new class of moons in the rings of Saturn that create idiosyncratic propeller-shaped gaps in ring material. It marks the first time scientists have been able to track the orbits of individual objects in a debris disk. The research gives scientists an occasion to time-travel back into the history of our solar system to reveal clues about disks around other stars in our universe that are too far away to observe directly.

"Observing the motions of these disk-embedded objects provides a rare opportunity to gauge how the planets grew from, and interacted with, the disk of material surrounding the early sun," said Carolyn Porco, Cassini imaging team lead based at the Space Science Institute in Boulder, Colo., and a co-author on the paper. "It allows us a glance into how the solar system ended up looking the way it does."

The results are available in a new study in the July 8, 2010, issue of the journal Astrophysical Journal Letters.

Cassini scientists first discovered double-armed propeller features in 2006 in an area now known as the "propeller belts" in the middle of Saturn's outermost dense ring, well-known as the A ring. The spaces were created by a new class of moonlets - smaller than known moons, but larger than the particles in the rings - that could clear the space instantly around them. Those moonlets, which were predictable to number in the millions, were not large enough to clear out their entire path around Saturn, as do the moons Pan and Daphnis.

The new paper, led by Matthew Tiscareno, a Cassini imaging team associate based at Cornell University, Ithaca, N.Y., reports on a new cohort of larger and rarer moons in another part of the A ring farther out from Saturn. With propellers as much as hundreds of times as large as those formerly described, these new objects have been tracked for as long as four years.

The propeller features are up to several thousand kilometers (miles) long and several kilometers (miles) wide. The moons embedded in the ring emerge to kick up ring material as high as 0.5 kilometers (1,600 feet) above and below the ring plane, which is well beyond the typical ring thickness of about 10 meters (30 feet). Cassini is too far away to see the moons amid the swirling ring material around them, but scientists guess that they are about a kilometer (half a mile) in diameter because of the size of the propellers.

Tiscareno and colleagues estimate that there are dozens of these giant propellers, and 11 of them were imaged multiple times between 2005 to 2009. One of them, nicknamed Bleriot after the famous aviator Louis Bleriot, has been a veritable Forrest Gump, showing up in more than 100 separate Cassini images and one ultraviolet imaging spectrograph observation over this time.

"Scientists have never tracked disk-embedded objects anywhere in the universe before now," Tiscareno said. "All the moons and planets we knew about before orbit in empty space. In the propeller belts, we saw a swarm in one image and then had no idea later on if we were seeing the same individual objects. With this new discovery, we can now track disk-embedded moons individually over many years."

Over the four years, the giant propellers have shifted their orbits, but scientists are not yet sure what is causing the disturbances in their travels around Saturn. Their path may be upset by bumping into other smaller ring particles, or responding to their gravity, but the gravitational magnetism of large moons outside the rings may also be a factor. Scientists will continue monitoring the moons to see if the disk itself is driving the changes, similar to the interactions that happen in young solar systems. If it is, Tiscareno said, this would be the first time such a measurement has been made directly.

"Propellers give us unexpected insight into the larger objects in the rings," said Linda Spilker, Cassini project scientist based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Over the next seven years, Cassini will have the chance to watch the evolution of these objects and to figure out why their orbits are changing."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission Directorate in Washington. The Cassini orbiter and its two onboard cameras were intended, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.

Wednesday, July 7, 2010

This raw, unprocessed image of Saturn's moon Daphnis orbiting in a rift in Saturn's rings was taken on July 5, 2010, by NASA's Cassini spacecraft. Image credit: NASA/JPL/Space Science Institute

A new image from the Planck mission shows what it's been up to for the past year -- surveying the whole sky for clues to our universal origins. Planck, a European Space Agency mission with significant participation from NASA, has been effectively scanning the whole sky at nine frequencies of light, with the final goal of isolating fluctuations in the cosmic microwave background -- or light from the beginning of time. These fluctuations symbolize the seeds from which organization in our universe evolved.

NASA's Cassini spacecraft has captured the closest images of Saturn's moon Daphnis to date. In these raw images obtained on July 5, 2010, the moon can be seen orbiting in a rift well-known as the Keeler Gap in one of Saturn's rings.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini mission for NASA's Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter.

Tuesday, July 6, 2010

Evidence for a recoiling black hole has been found using data from the Chandra X-ray Observatory, XMM-Newton, the Hubble Space Telescope (HST), and numerous ground-based telescopes. This black hole kickback was caused either by a slingshot effect produced in a triple black hole system, or from the possessions of gravitational waves produced after two supermassive black holes merged a few million years earlier.

The discovery of this object, located in this composite image, comes from a large, multi-wavelength survey, known as the Cosmic Evolution Survey (COSMOS). This survey includes data from Chandra, HST, XMM- Newton, as well as ground-based observatories. Of the 2,600 X-ray sources found in COSMOS, only one -- named CID-42 and located in a galaxy about 3.9 billion light years away -- coincides with two very close, compact optical sources (The two sources are seen in the HST data, but they are too close for Chandra to resolve separately.) In this image, the X-ray source detected by Chandra is tinted blue, while the Hubble data are seen in gold.

The galaxy's long tail suggests that a merger between galaxies has occurred relatively newly, only a few million years earlier. Data from the Very Large Telescope and the Magellan telescope give evidence that the difference in speed of the two optical sources is at least three million miles an hour.

The X-ray spectra from Chandra and XMM-Newton provide additional information about CID-42. Absorption from iron-rich gas shows that gas is moving quickly away from us in the rest frame of the galaxy. This could be gas in the galaxy between us and one of the black holes that is falling into the black hole, or it could be gas on the far side of the black hole that is blowing away.

Taken together, these pieces of information permit for two different scenarios for what is happening in this system. In the first scenario, the researchers surmise that a triple black hole come across was produced by a two-step process. First, a collision between two galaxies twisted a galaxy with a pair of black holes in a close orbit. Before these black holes could merge, another galaxy collision occurred, and another supermassive black hole spiraled toward the accessible black hole pair.

The interaction among the three black holes resulted in the lightest one being expelled. In this case, the optical source in the lower left of the image is an active galactic nucleus (AGN) powered by material being pulled along by, and falling onto, the escaping supermassive black hole. The source in the upper right is an AGN containing the black hole that resulted from a merger between the two enduring black holes.

In this slingshot scenario, the high-speed X-ray absorption can be explained as a high-speed wind blowing away from the AGN in the upper right that absorbs light from the AGN in the lower left. Based on its optical spectrum, the AGN in the upper right is thought to be hidden by a torus of dust and gas. In nearly all cases a wind from such an AGN would be undetectable, but here it is illuminated by the other AGN, giving the first evidence that fast winds exist in obscured AGN.

An alternative explanation posits a merger between two supermassive black holes in the center of the galaxy. The irregularity of the gravitational waves emitted in this process caused the merged black hole to be kicked away from the center of the galaxy. In this scenario, the evicted black hole is the point source in the lower left and a cluster of stars left behind in the center of the galaxy is in the upper right. The observed X-ray absorption would be caused by gas falling onto the recoiling black hole.

Future observations may help eradicate or further support one of these scenarios. A team of researchers led by Francesca Civano and Martin Elvis of the Harvard-Smithsonian Center for Astrophysics (CfA) will circulate their work on CID-42 in the July 1st edition of The Astrophysical Journal.

The second scenario, about the recoil of a supermassive black hole caused by a gravitational wave kick, has recently been proposed by Peter Jonker from the Netherlands Institute for Space Research in Utrecht as a probable explanation for a source in a different galaxy. In this study, led by Peter Jonker from the Netherlands Institute for Space Research in Utrecht, a Chandra X-ray source was discovered about ten thousand light years, in projection, away from the center of a galaxy. Three potential explanations for this object are that it is an unusual type of supernova, or an ultraluminous X- ray source with a very bright optical counterpart or a recoiling supermassive black hole resulting from a gravitational wave kick.

Friday, July 2, 2010

NASA's next Mars rover, Curiosity, is sitting appealing on a set of spiffy new wheels that would be the desire of any car show on Earth.

The wheels and a deferral system were added this week by spacecraft technicians and engineers. These new and significant touches are a key step in assembling and testing the flight system in advance of a planned 2011 launch.

Curiosity, centerpiece of NASA's Mars Science Laboratory mission, is a six-wheeler and uses a rocker-bogie deferral system like its smaller predecessors: Spirit, Opportunity and Sojourner. Each wheel has its own drive motor, and the corner wheels also have sovereign steering motors. Unlike earlier Mars rovers, Curiosity will also use its mobility system as a landing gear when the mission's rocket-powered tumble stage lowers the rover directly onto the Martian surface on a tether in August 2012.

In coming months at NASA's Jet Propulsion Laboratory, the mobility system will get practical testing and be part of environmental testing of the rover. The mobility system will now stay on Curiosity through launch unless testing identifies a need for rework that would oblige it to be disassembled.

The mission will launch from Florida during the period Nov. 25 to Dec. 18, 2011. Curiosity will examine an area of Mars for modern or ancient livable environments, including any that may have also been approving for preserving clues about life and environment, though this mission will not seek confirmation of life. It will examine rocks, soil and atmosphere with a varied payload of tools, including a laser to vaporize patches of rock from a distance and an instrument intended to test for organic compounds.

Thursday, July 1, 2010

Engineers are studying the reaction wheels on NASA's Dawn spacecraft after automatic sensors detected surplus friction building up in one of them and powered it off early on the morning of June 17, 2010. Reaction wheels spin to help a spacecraft maintain position control, and Dawn, which is exploring the asteroid belt, uses three wheels in standard operations.

The three other reaction wheels are working normally. Mission managers said plans for Dawn to visit the asteroid Vesta in 2011 and 2012 and dwarf planet Ceres in 2015 will not be not pretentious.

"We're looking at the data carefully in order to understand what the long-term prospects are for this reaction wheel," said Marc Rayman, Dawn's chief engineer, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "In the meantime, we're enduring our planned activities with the spacecraft." The spacecraft resumed ion thrusting on schedule, on June 24.

Flight controllers had uploaded software to Dawn's primary voyage computer on June 15. As a planned part of that activity, all four reaction wheels had been powered on. Two days later, while the spacecraft was not performing any science or engineering activities, the one reaction wheel built up surplus friction. The spacecraft's fault protection system acted as designed and turned the wheel off.

Engineers are analyzing what caused the friction buildup on the reaction wheel. But they do not consider the new software, the reactivation of the spacecraft, or a current velocity change triggered the reaction wheel issue.

The Dawn mission to Vesta and Ceres is managed by JPL, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. The University of California, Los Angeles, is accountable for overall Dawn mission science. Other scientific partners include Planetary Science Institute, Tucson, Ariz.; Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany; DLR Institute for Planetary Research, Berlin, Germany; Italian National Institute for Astrophysics, Rome; and the Italian Space Agency, Rome. Orbital Sciences Corporation of Dulles, Va., designed and built the Dawn spacecraft.